Re: Solvent-laden rag transport

Scott Schuler (
Tue, 13 Feb 1996 14:36:48 -0500

I just wanted to add to Dave Salman's description of the "Minnesota Model"
for managing printer shop towels contaminated with press wash. Dave's
description was accurate for the most part. The driving force within the
Minnesota printing industry actually came from the commercial laundries. The
laundries were risking enforcement action by the Metropolitan Council
Wasterwater Services Division if they did not take action to correct the high
LEL levels in their wastewater discharges. Their corrective action included
a decision to eliminate all printer shop towel customers who were unable to
reduce the percent soil (read as solvent) weight in their used towels to 100%
of the clean towel's weight.

This decision on behalf of the laundry drove the larger printers to invest in
centrifuge equipment, the medium size printers to use a mobile centrifuging
service, and the smaller printers to wring out their towels by hand. Roller
wringer devices have never really performed very well for printers. The
rubber rollers on these wringers disintegrate very quickly. Unscientific,
but carefully controlled tests at printers show that centrifuging is by far
the most effective method for removing solvents, followed by hand wringing,
with roller ringing the least effective.

The Minnesota Pollution Control Agency has produced a four page fact sheet on
this subject entitled, "Managing Towels, Wipes and Sorbents" (4/95) and can
be obtained from their fax on demand services at (612) 397-8918. I have also
created my own flow chart version of the various management options for
solvent contaminated towels in Minnesota.



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